SQL Insert with Identity value AND incremental rollover column ?

Question

Post reply

SQL Insert with Identity value AND incremental rollover column ?

RobRud

SSC Veteran

Points: 260
More actions
February 26, 2014 at 11:21 am

#288657

Hi
I need to create an INSERT query that will create new rows with a normal identity column, and in another integer column: increment (and rollover) a three-digit number. I'm using MSSQL Server 2008 r2.
Similar to the (incorrect) code below, I have a table and I need an INSERT procedure that will increment the MBatch column from 1 to 999, then rollover back to 1 on the next row insert. For example: the last row (identity=1111) may have MBatch=999, so when I insert new row (1112) I need MBatch=1).
When I call the INSERT procedure, I will pass it the "@MStatus" value, and would like the proc to return the Identity column value and the MBatch value.
Any suggestions?
Thanks!
CREATE TABLE [dbo].[MTRANS]
([MTRANS_ID] int IDENTITY (1, 1) NOT NULL,
[MBatch] int NULL,
[MStatus] char(1) NULL
)
CREATE PROCEDURE [prMTRANS_INSERT]
(@MTRANS_ID int OUTPUT,
@MStatus char(1),
@MBatch int OUTPUT
)
As
BEGIN
Begin
select MAX([MTRANS_ID]), [MBatch] from [MTRANS]
-- this bit is not correct, but you get what I'm going for ...
SET @mbatch = [MBatch]
if @mbatch >= 999
begin
set @mbatch = 1
end
else
set @mbatch = @mbatch +1
INSERT INTO [MTRANS]([MStatus], [MBatch)
VALUES (@mstatus,@mbatch)
End
SELECT @@IDENTITY as TRANS_ID, @mbatch as BATCHNO
END

Viewing 5 posts - 1 through 4 (of 4 total)

You must be logged in to reply to this topic. Login to reply

Dwain Camps SSC Guru Points: 86908 More actions · Answer 1

Something like this?

CREATE TABLE #MTRANS

([MTRANS_ID] int IDENTITY (1, 1) NOT NULL,

[MBatch] int NULL,

[MStatus] char(1) NULL

);

-- Create 10 rows

WITH Tally (n) AS

(

SELECT TOP 10 ROW_NUMBER() OVER (ORDER BY (SELECT NULL))

FROM sys.all_columns a CROSS JOIN sys.all_columns b

)

INSERT INTO #MTRANS (MBatch)

SELECT n

FROM Tally;

DECLARE @MBatch INT =(SELECT MAX(MBatch) FROM #MTRANS);

-- Create 999 rows with rollover at 300

WITH Tally (n) AS

(

SELECT TOP 999 ROW_NUMBER() OVER (ORDER BY (SELECT NULL))

FROM sys.all_columns a CROSS JOIN sys.all_columns b

)

INSERT INTO #MTRANS (MBatch)

SELECT 1+(@MBatch+ROW_NUMBER() OVER (ORDER BY n)-1)%300

FROM Tally;

SELECT *

FROM #MTRANS

GO

DROP TABLE #MTRANS;

My mantra: No loops! No CURSORs! No RBAR! Hoo-uh![/I]
My thought question: Have you ever been told that your query runs too fast?

My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.

Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St

mickyT SSChampion Points: 10360 More actions · Answer 2

The problem I see with your procedure is that the @mbatch variable is not set to the max.

If you alter your procedure to the following it should work.

CREATE PROCEDURE [prMTRANS_INSERT]

(@MTRANS_ID int OUTPUT,

@MStatus char(1),

@MBatch int OUTPUT

)

As

BEGIN

Begin

-- Changed your query here

SELECT TOP 1 @mbatch = [MBatch] FROM [MTRANS] ORDER BY [MTRANS_ID] DESC

--SET @mbatch = [MBatch] -- Remove this

if @mbatch >= 999

begin

set @mbatch = 1

end

else

set @mbatch = @mbatch +1

INSERT INTO [MTRANS]([MStatus], [MBatch])

VALUES (@mstatus,@mbatch)

End

SET @MTRANS_ID = SCOPE_IDENTITY()

-- SELECT @@IDENTITY as TRANS_ID, @mbatch as BATCHNO -- Not sure if you want to do this

END

Tested with

declare @oMID INT, @oBatch INT

exec prMTRANS_INSERT @MTRANS_ID = @oMID , @MStatus = 'B', @MBatch = @oBatch

GO 1500

SELECT * FROM [MTRANS]

Having said that, are all of your inserts one at a time and are they all through this procedure? You may run into issues if they aren't.

In 2012 you could use a sequence with cycling as the default value on the batch.

Edit: Fixed a syntax error and return values

Jeff Moden SSC Guru Points: 1003863 More actions · Answer 3

Avoid the RBAR. Make a persisted computed column that uses a formula like MTRANS_ID%999+1. Yeah... it'll have gaps, now and again... just like the IDENTITY column

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

RobRud SSC Veteran Points: 260 More actions · Answer 4

I've never used a "computed column", but I tried it and it will solve my problem.

Thanks!